To study space attack-defense technology, a simulation of satellites is needed. We design and implement a 3d simulating
system of satellites. The satellites are rendered under the Night sky background. The system structure is as follows: one
computer is used to simulate the orbital of satellites, the other computers are used to render 3d simulation scene. To get a
realistic effect, a three-channel multi-projector display system is constructed. We use MultiGen Creator to construct
satellite and star models. We use MultiGen Distributed Vega to render the three-channel scene. There are one master and
three slaves. The master controls the three slaves to render three channels separately. To get satellites' positions and
attitudes, the master communicates with the satellite orbit simulator based on TCP/IP protocol. Then it calculates the
observer's position, the satellites' position, the moon's and the sun's position and transmits the data to the slaves. To get
a smooth orbit of target satellites, an orbit prediction method is used. Because the target satellite data packets and the
attack satellite data packets cannot keep synchronization in the network, a target satellite dithering phenomenon will
occur when the scene is rendered. To resolve this problem, an anti-dithering algorithm is designed. To render Night sky
background, a file which stores stars' position and brightness data is used. According to the brightness of each star, the
stars are classified into different magnitude. The star model is scaled according to the magnitude. All the stars are
distributed on a celestial sphere. Experiments show, the whole system can run correctly, and the frame rate can reach
30Hz. The system can be used in a space attack-defense simulation field.